Durst L184 Anyone???

[Allen in Montreal]

Hi Len,

When I gave Lady Durst a cleaning I used optical cleaner that contains no ammonia etc that I bought at an optometrist just to be sure. I used it on the condensors and the mirror without issue. I never thought to check if it was front of rear silvered, but the mirror survived fine.

[Len Middleton]

Allen,

Thanks.

I removed the smaller mirror and looked at the corner closely and found I could see the edge of the glass from the front, indicating it was silverd on the back, not the front.

Thinking about it further, it makes sense as the requirement of the two mirrors is to redirect collimated light to get the correct distance for the focal length of the condensers and enlarging lens. The light at that point has not passed though a negative, and therefore does not contains image information. No need for the expense and frailty of a front silvered mirror at that point of the enlarger.

Now to find or fix a lensboard for the big 360mm f5.6 Componon, or find a suitable VALPLA to use or modify.

Regards,

Len

[ic-racer]

Allen,

Thanks.

I removed the smaller mirror and looked at the corner closely and found I could see the edge of the glass from the front, indicating it was silverd on the back, not the front.

Thinking about it further, it makes sense as the requirement of the two mirrors is to redirect collimated light to get the correct distance for the focal length of the condensers and enlarging lens. The light at that point has not passed though a negative, and therefore does not contains image information. No need for the expense and frailty of a front silvered mirror at that point of the enlarger.

Now to find or fix a lensboard for the big 360mm f5.6 Componon, or find a suitable VALPLA to use or modify.

Regards,

Len

I have the 360 mounted on a VAPLA with this fancy cone-shaped flange, but it is too long for vertical printing. More useful for horizontal printing. Will you be wall projecting?

[Len Middleton]

ic,

Yes, that is exactly the lens I have (other than the serial number). I did not do the math prior to purchasing the lens, but now see what you mean.

For a 300mm lens for a 2.5 magnification (8x10 => 20x25), a 300mm enlarging lens needs 58" from the negative stage to the paper, while the 360mm needs about 70".

I guess I should hold off getting any 20x24 trays and easels, and just work with the 16x20 (53" and 64" instead).

Maybe I need to look for a 300mm lens...

Thanks for reminding me of that limitation, as I have not got it set up for horizontial projection.

Len

[gary mulder]

If you have the condensers for a 240mm lens, thats the one to look for. Rodagon or componon-s

[Len Middleton]

Gary,

The Durst condenser system appears to be extremely well thought out, but there are some limitations with it.

The Durst USA site has a good descritpion of the condenser system, and one of the limitations mentioned is the coverage of the condesers. The Durst L184 guide lists the 240mm lens but for the 5x7 format, not the 8x10 format that I use.

The 240mm lens will work with a diffusion enlarging head for 8x10, but not the condenser head.

Thank you for your thoughts on this,

Len

[gary mulder]

You are right. The lacon 250 is not big enough for 8x10

[Len Middleton]

For a 300mm lens for a 2.5 magnification (8x10 => 20x25), a 300mm enlarging lens needs 58" from the negative stage to the paper, while the 360mm needs about 70".

I guess I should hold off getting any 20x24 trays and easels, and just work with the 16x20 (53" and 64" instead).

Maybe I need to look for a 300mm lens...

With current installation, it is about a maximum of 54" (might be able to squeeze a little more, but not much) from negative stage to baseboard, so indeed a 300mm lens does look much more attractive...

[Len Middleton]

The clamping bolt for the enlarger head elevation system (hand crank, rather than motor on my unit) is missing, so went to the local hardware / building centre and got a 12mm diameter bolt for it. With the hand crank in place, the bolt does not drop in place, but will drop in with the hand crank removed.

It looks like I will need to modify the 12mm bolt to allow the hand crank to be installed, then tighten the bolt to clamp the hand crank. Is that indeed how the system works, or is there some other way of doing it? Could someone with that system please describe the modifications done to the bolt shank. I can speculate, but best if someone describes it for me...

Thanks for eveyones help on this project,

Len

[ic-racer]

Here you go (Link points to Componon 300mm with flange for $200 BIN,good deal!): http://cgi.ebay.com/SCHNEIDER-KREUZN...item3cb8d38281